u/Individual_Base8208

This is a banjo that uses a balloon as its resonating chamber.

When you pluck the strings, the sound resonates inside the balloon. The sound changes depending on two factors: how much you inflate the balloon and how tightly you tension the strings.

You can feel with your own hands how the resonance shifts as the volume of air changes.

The design allows both the balloon and the strings to be replaced.

Try inserting a balloon of a different size. Experiment with string thickness.

Try it out, revert to the previous setup, and try again—this toy was created to encourage that kind of experimentation.